ironic.common.fsm module¶

service None

Bases: automaton.machines.FiniteMachine

An ironic state-machine class with some ironic specific additions.

FSM.add_state(state, on_enter=None, on_exit=None, target=None, terminal=None, stable=False)[source]¶

Adds a given state to the state machine.

Parameters:	stable – Use this to specify that this state is a stable/passive state. A state must have been previously defined as ‘stable’ before it can be used as a ‘target’ target – The target state for ‘state’ to go to. Before a state can be used as a target it must have been previously added and specified as ‘stable’

Further arguments are interpreted as for parent method add_state.

FSM.add_transition(start, end, event, replace=False)¶

Adds an allowed transition from start -> end for the given event.

Parameters:	start – starting state end – ending state event – event that causes start state to transition to end state replace – replace existing event instead of raising a Duplicate exception when the transition already exists.

FSM.initialize(start_state=None, target_state=None)[source]¶

Initialize the FSM.

Parameters:	start_state – the FSM is initialized to start from this state target_state – if specified, the FSM is initialized to this target state. Otherwise use the default target state

FSM.is_stable(state)[source]¶

Is the state stable?

Parameters:	state – the state of interest
Raises:	InvalidState if the state is invalid
Returns:	True if it is a stable state; False otherwise

FSM.process_event(event, target_state=None)[source]¶

process the event.

Parameters:	event – the event to be processed target_state – if specified, the ‘final’ target state for the event. Otherwise, use the default target state